On the basis of clinical experiences in the area of both medical and surgical treatment of ventricular irritability due to ischemic heart disease it is felt that some attempt at investigating this heretofore unsuccessfully treated condition was warranted. We are going to attempt to construct a reproducible model for the production of ventricular tachyarrhythmias in experimental animals, probably by ligation of one or more coronary arteries and administration of ouabain. Secondly, attempts to localize the irritable foci will be made by epicardial, myocardial, and endocardial electrical mapping of the heart. It is our feeling that because the Purkinje system is located in the subendocardial layers we feel strongly that this is the area of heart muscle which will be most likely to be productive in terms of localizing arrhythmogenic foci. If these foci can be satisfactorily localized it would seem justifiable that chemical, cryo or surgical oblation should be evaluated.